Nonvolatile N-nitroso compounds, especially the N-nitrosamides, have been implicated as possible causative agents in gastric and other cancers. N-nitrosamides are also known to be rapidly formed from their precursors under a wide variety of conditions. At present, it is not known whether these highly carcinogenic compounds are present in human body fluids, or whether they are contained in foodstuffs, cosmetics, drugs, or pesticides. This paucity of knowledge is due entirely to the lack of viable analytical chemistry procedures for the analysis and detection of these compounds at the part-per-billion sensitivity level. In preliminary experiments, it has been shown that a minor modification to a conventional TEA nitrosamine analyzer will render it highly sensitive and selective to the N-nitrosamides. This knowledge will be exploited to develop analytical procedures for these compounds, and to seach for them in human gastric aspirates, and in selected matrices where they are suspected of being present. The long-term aim of the project is to determine whether the nonvoltaile N-nitroso compounds are present in man (body fluids) or in the products he consumes (food, cosmetics, pesticides, etc.) in sufficient quantity to be suspect in the etiology of human cancer.